The present invention relates to a method of connecting a terminal to an insulated electrical wire, which is particularly suitable for use on multicore cables of small diameter to facilitate their use in the wiring systems of motor vehicles, particularly for the distribution of control signals.
In many wiring systems it is desirable to use extremely small conductors, especially for lines which are to carry low power signals such as data or control signals, since it is often preferable to reduce the weight and bulk of the wiring system and also to economise on the materials of the conductors, which account for a large part of the cost of a wiring system. In addition the use of bundles of extremely small wires, termed "micro-cables" is often preferable in systems involving a large number of wires.
The term micro-cable as used in the specification, will be understood to refer to a cable having a plurality of conductive wires each having a diameter of the order of tenths and hundredths of a millimeter, and being provided with an individual insulating layer. Normally an outer insulating cover would be provided to hold the individual wires together as a single cable. It is possible to employ transceivers associated with various components, particularly for the distribution of data signal or control signals, in order to reduce the number of wires in a wiring system, and therefore reduce the bulk and complexity of the system as a whole. With such an arrangement coded modulation signals carried by one wire (single-wire installation) or by two wires (double-wire installation) are used. However, the cost of apparatus of this type is so high that its use is only justifiable in sophisticated systems such as are found, for example, on board aeroplanes.
Thus, for the transmission of control signals on motor vehicles, where the use of such sophisticated techniques is not justified, it is necessary to use conductor systems in which control signals are conducted individually on separate conductors to the various components. The conductors may be constituted, for example, by the wires of one or more micro-cables. One advantageous chracteristic of systems utilising micro-cables is that, since each wire has a very small overall dimension, more wires than are necessary can be used to produce a redundant system equipped with multiple circuits, thereby more effectively ensuring security of operation and effectual transfer of a signal. Up to the present, however, the utilization of micro-cables have been difficult largely because of the small diameter of the component wires, which is such an advantage in other respects. The small size makes the wires difficult to manipulate, and operating on such wires to form connections with conventional methods and equipment, even if possible at all, is extremely difficult, time consuming and thus expensive.